Compressor apparatus



I March 14, 1939. 5. BROWN 2,150,487

COMPRESSOR APPARATUS Filed June 4, 1938 INVENTOR Jay/flour fir'oa/zzATTO R N EY lubrication is employed, the presence of ade- Patented Mar.14, 1939 PATENT OFFICE COMPRESSOR APPARATUS Seymour Brown, Syracuse, N.Y., assignor to Carrler Corporation, Syracuse, N. Y., a corporation ofDelaware Application June 4, 1938, Serial. No. 211,788

9 Claims.

This invention relates to compressor appara-- pressor is subsequentlyplaced in operation, this refrigerant leaves the crankcase duringequalization of crankcase and suction pressures and necessarily carrieswith it' considerable quantities of the oil by which it has beenabsorbed.

This results in insufllcient lubrication of the compressor,since whethersplash or forced-feed quate quantities of oil in the crankcase of thecompressor is essential to proper lubrication. Often irreparable damageis done to the compressor by reason of the insumcient lubrication duringthe starting-up period.

An object of the invention is to provide an apparatus for facilitatingequalization of crankcase and suction pressures during starting-upperiods, thereby to shorten such periods, and for thereafter, during anoperating period, maintaining the pressure of the crankcase at a lowerlevel than the pressure obtaining in the suction side of the compressor.The maintenance of such a pressure differential serves to provide forthe return of oil from the system to the crankcase and for the retentionof such oil in the crankcase, thus to assure adequate and properlubrication of the compressor.

Another object of the invention is to provide means for preventing thedelivery to the compressor of a refrigerating system of unevaporatedparticles of refrigerant passing from the evaporator of the system and,during the starting-up period, from the crankcase of thecompressor.

- A feature of the invention resides in providing, in conjunction withthe suction line or intake of the compressor of a refrigerating system,

' means for increasing the velocity and reducing the pressure \ofrefrigerant passing to the compressor, and a tube or the like, providingcommunication between the crankcase of the compressor and the lowpressure area thus created in the compressor suction line.Such-pressure-reducing means in the suction line may comprise, forexample, a venturi, nozzle or orifice arrangement. The low pressure thuscreated in the gas suction line serves to create in the crank case apressure which is lower than that of the suction line feeding thecompressor, so that after the starting-up period of operation oil isprevented from leaving the crankcase and is, in fact, returned to thecrankcase from the remainder of the system. Since at all times duringthe operation of the compressor subsequent to the starting-up periodthis arrangement pro-, vides for maintaining the pressure in thecrankcase lower than the pressure in the suction line, the circulationof oil through the refrigerating system is much reduced and practicallyeliminated. Thus, small quantities of oil may be used with greaterassurance of adequate lubrication throughout all portions of theoperating periods. Further, due to the retention of the major portion ofthe oil in the crankcase, larger quantities of oil may be utilized thanin conventional apparatus, with no increased circulation'of oilthroughout the system, as would oc-. cur if larger oil quantities wereused in conventional apparatus.

Also, the low pressure area formed in the gas suction line serves tofacilitate evaporation-of whatever particles of liquid refrigerant maybe drawn through the gas suction line from the evaporator or from thecrankcase during starting-up periods. This prevents slugging of thecompressor, which has been found especially troublesome in refrigeratingsystems of the compression type, particularly during the starting-upperiods of operation.

Other objects, features and advantages of th invention will be moreapparent from the following description to be read in conjunction withthe accompanying drawing, in which:

Fig. 1 diagrammatically represents, in vertical section, a compressorapparatus embodying the invention;

Fig. 2 is a fragmentary view on an enlarged scale of a portion of theapparatus of Fig. 1;

Fig. 3 is a fragmentary view similar to Fig. 2 illustrating amodification of the invention, and

Fig. 4 is a fragmentary view similar to Fig. 2 illustrating stillanother modification of the invention.

Referring now to the drawings, the numeral Ill designates generally acompressor having a casing H, a piston l2 and a crankcase [3, the

bottom of crankcase I 3 serving as an oil reservoir, the oil incrankcase l3 being indicated at ll. Piston I2 is driven throughconnecting rod l6 by crankshaft l6, which is driven in any suitablemanner, as by an electric motor or the like (not shown). Fluid to becompressed is supplied to the compressor l0 through suction line H andcompressed fluid is discharged from the compressor through dischargeline l8. Upon downward movement of the piston l2 fluid'is intaken withinthe body of the piston l2 through ports I! and is delivered throughpassages 20 to the compression chambendesignated 2|, upon opening ofsuction valve 22. Upon upward movement of the piston l2 the compressedfluid is discharged into discharge chamber 23 upon opening of dischargevalve '24, the compressed fluid then passing to discharge line I 6.

In the suction line H is formed a venturi 25 having a throat-portiondesignated 25a. As fluid is drawn through the suction line l1 and passesthrough throat portion 26a of the venturi, its velocity is increased andits pressure is reduced, in accordance with well-understood principles.The pressure reduction which thus occurs serves to facilitateevaporationof such liquid particles of refrigerant 'as may remainunevaporated by heat exchange in the evaporator (not shown) from whichthe suction line H supplies refrigerant to the compressor. Since suchliquid'particles areprevented from passing to the compressor, assuranceis thus provided against slugging of the compressor due to the presenceof liquid refrigerant drawn from the evaporator.

Tube 26 provides communication between the crankcase l3, from a pointabove the normal oil .level therein, and the area of low pressureproximate the throat of the venturi 25. As shown in Fig. 2, the tube 26may communicate with the venturi 25 at a point slightly beyond the mostconstricted portion of the venturi or, ii desired, may be connected tothat portion of the venturi which is most constricted. Upon operation ofthe compressor, the flow of fluid through suction line 81- and throughventuri 25 draws a relatively low pressure in the crankcase It, so thatthe pressure in the crankcase is always lower than the pressure in thesuction line IT. The relatively low pressure which is thus caused to bemaintained in the crankcase serves to prevent the oil of the crankcasefrom passing into other parts of the refrigerating system, and to eiIectthe return to the crankcase of oil which may be distributed throughoutthe system, and thus such oil may be eflleiently utilized to providedesired lubrication of the compressor. To prevent splashed oil particlesfrom entering within the tube 26 there is preferably provided a guardbaille or the like, 21, of any suitable design positioned over andprotecting the lower end of tube 26.

' In Fig. 3 is illustrated a modification of the invention in which theventuri 25 is replaced by a restricting member 26 provided with anorifice opening 29. The opening 29 is relatively small and hence fluidflowing through the suction line I] and the opening 29 travels past theupper extremity of tube 26 at relatively high velocity, thus creating alow pressure area at the upper extremity of the tubing 26 which servesto reduce the pressure in crankcase I3 in the manner explained above.

In Fig. 4. is illustrated another modification of the invention in whichthe same principle of operation is employed. In Fig. 4 a nozzle 36 isprovided for increasing the velocity of flow of fluid passing to thecompressor through suction line i 1, and the nozzle 30 is so arrangedthat its discharge end is proximate and surrounds the upper extremity oftube 26a. The low pressure area created at the upper end of tube 26a. bythe high velocity discharge from nozzle 36 serves to maintain thepressure in the crankcase 13 at a relatively low value.

During starting-up periods, oil and refrigerant are drawn from thecrankcase through tube 26. When such refrigerant, in the form of liquidparticles, passes into the low pressure area proximate the venturi 25 orthe like, these particles of refrigerant are vaporized, and slugging" isthus avoided.

While the invention has been described with particular reference to acompressor of the reciprocating type, it will be apparent that theinvention may be employed in conjunction with other types of compressorswithout departing from the scope of the invention.

Since many changes may be made in the invention without departing fromits scope, it is intended that all matter contained in the abovedescription or shown in the accompanying drawing shall be interpreted asillustrative only and not in a limiting sense, applicant limitinghimself only as indicated in the appended claims.

I claim: I

1. In a compressor apparatus including fluid compression means, a fluidsupply line and a crankcase, the combination of means for creatingwithin said fluid supply line an area in which the pressure issubstantially lower than the suction pressure of said compression means,and means for providing communication between said area of low pressureand said crankcase at a point above the normal oil level therein.

2. In a compressor apparatus including fluid compression means, meansfor supplying fluid to be compressed to said compression means, and anoil reservoir having a normal 011 level, the

combination of means for creating within said fluid supply means an areain whichthe pressure is substantially lower than the suction pressure ofsaid compression means, and means for providing communicationbetween-said area of low pressure and said oil reservoir at a pointabove for forming an area in which the pressure is substantially lowerthan the suction pressure of said compressor, and means providingcommunication between said area of low pressure and said crankcase at apoint above the normal oil level therein.

4. In combination with a compressor apparatus having an oil reservoirformed in the crankcase thereof and means for supplying to saidcompressor fluid to be compressed, means operative respcnsive to thesupply of fluid to said compressor for forming an area in which thepressure is substantially lower than the suction pressure of saidcompressor, and a conduit providing communication between said area oflow pressure and said crankcase at a point above the normal oil leveltherein.

5. In combination with a compressor apparatus having an oil reservoirformed in the crankcase thereof and means for supplying to saidcompressorfluid to be compressed, means operative responsive to thesupply of fluid to said compressor for forming an area of lower pressurethan the suction pressure of said compressor apparatus, saidlast-mentioned means comprising a venturi forming a part of said fluidsupply means, and a conduit providing communication between said area oflow pressure and said crankcase at a point above the normal oil leveltherein.

6. In combination with a compressor apparatus having an oil reservoirformed in the crankcase thereof and means for supplying to saidcompressor fluid to be compressed, means operative responsive to thesupply of fluid to said compressor for forming an area of lower pressurethan the suction pressure of said compressor apparatus, saidlast-mentioned means comprising a venturi forming a part of said fluidsupply means,

and means forming a passageway providing communication between thecrankcase of said compressor, at a point above the normal oil leveltherein, and the fluid supply means proximate the throat of saidventuri.

7. In combination with a compressor apparatus having an oil reservoirformed in the crankcase thereof and means forsupplying to saidcompressor fluid to be compressed, means operative responsive to thesupply of fluid to said a compressor for forming an area of lowerpressure than the suction pressure of said compressor apparatus, saidlast-mentioned means including means for restricting communicationbetween upstream and downstream portions of said fluid supply means,whereby fluid passing to the compressor will attain a relatively highvelocity proximate said communication-restricting means and thus form anarea of relatively low pressure proximate the downstream side of saidcommunication-restricting means, and means forming a passagewayproviding communication between said area of relatively low pressure andthe crankcase of said compressor above the normal oil level.

8. In combination with a compressor apparatus having an oil reservoirformed in the crankcase thereof and means for supplying to saidcompressor fluid to be compressed, means oper- 9. In combination with acompressor apparatus having an oil reservoir formed in the crankcasethereof and means for supplying to said compressor fluid to becompressed, means operative responsive to the supplyof fluid to saidcompressor for forming an area in which the pressure is substantiallylower than the suction pressure of said compressor apparatus, saidlastmentioned means includinga nozzle formation through which fluidpassing from the upstream portions of said fluid supply means to thedownstream portions thereof is routed, and means forming a passagewaycommunicating between the area of relatively low pressure formedproximate the discharge end of said nozzle formation and the crankcaseof said compressor above the normal oil level therein.

. SEYMOUR BROWN.

DISCLAIMER 2,150,487.Seymom' Brown, Syracuse, New York. COMPRESSORAPPARATUS. Patent dated March 14, 1939. Disclaimer filed July 26, 1940,by the assignee, Carrier Corporation. Hereby enters this disclaimer toclaims 1, 2, 3, 4, 5, 6 and 7 of said Letters Patent.

[Ofiic'ial Gazette August 27, 1940.]

